Abstract
We present a case report of postoperative pain following THR, which was initially diagnosed as infection. The salutary message is that the correct diagnosis was a secondary tumour.
A fifty three year old man had a primary right total hip replacement for osteoarthritis, using an uncemented CAD CAM (computer aided design, computer aided manufacture) prosthesis with a Trilogy cup. Postoperatively he recovered uneventfully, with a normal range of movement and good function; there were no radiographic abnormalities noted at the time. Two years after operation, he developed pain in the right thigh. His doctor referred him for investigation of his back, which was normal. He was then seen by an orthopaedic surgeon who diagnosed infection, based on an X-ray that revealed a destructive lesion of the upper femur. He was referred back to the senior author, who felt that the X-ray was more suggestive of tumour than infection; further investigation, with MRI and ultrasound confirmed the presence of a tumour; isotope bone scanning revealed it to be solitary. A needle biopsy showed follicular thyroid tumour to be present; this was confirmed by immunohistochemistry. His past medical history included a history of hemithyroidectomy eight years prior to the hip replacement – this was for what was believed to be a benign thyroid nodule. CT of his chest revealed multiple lung metastases.
Review of the X-ray taken six months post-operatively suggests, in retrospect, that the destructive process had already begun. He has been treated with a total thyroidectomy and radiotherapy to the right hip with encouraging early results. He is also having chemotherapy for the pulmonary metastases. Thyroid tumours metastasise by blood and commonly occur in bone; the proximal femur is a frequent site for metastasis. It is likely that the occurrence is coincidental.
Theses abstracts were prepared by Mr Peter Kay. Correspondence should be address to him at The Hip Centre, Wrightington Hospital, Appley Bridge, Wigan, Lancashire WN6 9EP.
